Luther pullxam



v.(No Model.) A Y L. PULLIAM.

BRIDGE.

Patented Apr. 4, 1893.

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UNITED STATES PATENT OFFICE.

LUTHER FULLIAM, OF S'l. LOUIS, MISSOURI, ASSIGNOR TO RICHARD M.

SORUGGS, OF SAME PLACE.

BRIDGE.

SPECIFICATION ,forming part of Letters Patent No. 495,005, dated April4, 1893. Application filed June l0, 1892. Serial No. 436,253. (Nomodel.)

To @ZZ whom t may concern:

Be it known that I, LUTHER PULLIAM, of St. Louis, Missouri, have made anew and useful Improvement in Bridges, of which the following is a full,clear, and exact description.

The improvement relates more especially to truss-bridges, and itconsists mainly in certain structural features of the trusses,substantially as is hereinafter set forth and claimed, aided by theannexed drawings, making part of this specification, in which- Figure lis a side elevation of the improved bridge; Fig. 2 a plan of the bridge;Fig. 3 an end elevation of the bridge; Fig. 4 a vertical cross-sectionof aportion ot' one of the trusses, the section being on the line 4-4 ofFig. l;

' Fig. 5 a side elevation, partly in section, of a portion of one of thetrusses; Fig. 6 a View in perspective of one of the truss-straps; Fig. 7a detail, partly in elevation and partly in section, showing the end ofone ot the crossbraces and the member of the truss against which thebrace abuis; Fig. 8 a View in perspective showing an end of the lowerportion of one of the trusses, but omitting the straps and ties; andFig. 9 a view analogous to that of Fig. 8, but showing a modification inrespect to the relative arrangement of the upright and horizontalmembers of the truss.

The same letters of reference denote the same parts.

A and A represent the trusses of the bridge. They are suitably united bymeans ofthe inclined cross-braces, B, and the horizontal braces C. Theioor timbers, D, may also serve to connect the trusses. Each truss,considered generally comprises a lower member E, and an upper member F.The lower member is mainly in tension,and the upper member incompression. The lower member is of a composite nature, consistingsubstantially oi horizontal chords e, e', e2, nprights, e3, and ties e4.The chords, in one form of the construction, are used in pairs, and theuprights are arranged between them--substantially as shown in Figs. l, 5and 8, and in another form of the construction the uprights are used inpairs, and the chords are between them, substantially as shown in Fig.9. In either case the chords and upright-.s are suitably fastenedtogether (fastenings not shown) to enable the uprights to serve both asties and as posts in connecting the chords to form the member E. Theties e, are a valuable auxiliary in uniting the chords in a verticaldirection. They are preferably in the form of a band e5, shaped to passaround the combined parts, e, c', duc., and to be secured thereto bymeans of suitable plates c, and nuts c7, substantially as shown.

An additional feature of the member E is the inclined braces or ties G.They are introduced into the member E usually in the same plane, orplanes, with that or those ot the uprights, and they extend, as shownmore distinctly in Fig. 5, from one upright to another, and like theuprights they are suitably fastened to the chords and thus serve asbraces between the uprights and also as ties to connect the chords.

I desire not to be restricted to a certain number of chords in theconstruct-ion of the member F.; three are shown, but two, three, or moremay be used. The uprights, straps, and inclined braces are adapted tothe number of chords used and their relative arrangement. Suitablespacing blocks, Il, are used between the chords, substantially asdescribed.

The above described method of construct ing the member E is a desirableone irrespective of the remaining' features of the truss to bedescribed. The member in itself constitutes a bridge-truss, and it canbe used as such. I prefer, however, to employ in conjunction therewiththe upper member F, and also an underneath truss I, and to connect thetwo members and the last named part substantially as follows: The memberF is angled, crowned, or bowed to act substantially as an arch; that is,the member, from the ends respectively of the truss, inclines upward,and its highest point is midway in the length of the truss. It may be asingle piece, but it is generally of a composite nature. It is connectedwith the lower member by means of suitable ties, such for instance asthe straps J, and in addition thereto the uprights of the lower membermay be extended upward to be connected with the upper member, substan-IOO tially as shown at e3, Fig. l. Said extended uprights may be used asthe only connections with the lower member.

In addition to ties extending vertically, or in lieu of them, inclinedties, such for instance as the straps K, may be used to con neet theupper and lower members of the truss. Although but two such inclinedties are represented in the drawings, and which are arrangedrespectively toward the endsof the truss, others can be employed of asimilar nature and arranged atsuitable intervals throughout the lengthof the truss. There may, for instance, be one for each panel of thetruss. As represented they pass around the upper member and also aroundthe lower member, but I desire not to be restricted to this form of tie,as obviously other forms can be used. These inclined ties as stated maybe the sole means for connecting the members E, F, but I preferablyemploy the two forms, namely, the vertical and the inclined inconjunction. The underneath truss I, is a leading :feature of theconstruction. It is composed mainly of three parts; a horizontal part,1,', arranged beneath the central portion of the member E, and twoinclined parts v, arranged respectively at the ends of the truss andconnected with said central part fz', and the remainder of theconstruction as follows: the parts i', i', at their outer endsrespectively are secured to the end-portions respectively of the truss,and preferably at the ends of the upper member F, as shown, and thencethey extend downward and inward to meet the horizontal part t', and toconnect therewith `in any desirable manner. In the drawings theconnection with the horizontal part t', is by means of the shoulders o?,around which the ties i', i', respectively pass. But any other mode ofconnecting the parts ,t", i', may be employed, and the parts t', z", i',may be of any shapes adapted to the purpose in question. That is to say,the horizontal part i serves to increase the depth of the truss at itscentral portion, and to that end the parteis connected with the memberE, by means of the straps and the uprights substantially as shown, or byother equivalent means, and also preferably with the member F by meansof the extended straps and uprights, substantially as shown, or otherequivalent means, and also suitably spaced apart from the member E. Thusit will be seen the truss is materially strengthened at its centralportion, and the underneath truss serves not only to increase thetensile strength of the lower member of the truss but also to act as atruss for the overhead member F, as well as to bind the two members E,F, together. In carrying out this last mentioned feature of theconstruction I desire not to be confined to the single underneath truss,as additional ones of a similar nature may be employed. That is, theremay be additional parts similar to the part t, arranged eithersuccessively beneath each other or side by side, and each, by means ofties, such as the ties i', connected wlth the structure above, and atthe ends of the truss as are the parts i', i', or at other suitablepoints.

In carrying out the present improvement the upper and lower members, E,F, may be connected at or toward their ends only and the advantages ofthe improvement in a measure thereby be obtained. I prefer however toconnect said members not only at their ends but also at various pointsbetween their ends substantially as is represented. I desire not to berestricted to any special means in connecting said members at the pointsnamed, but prefer the means exhibited. .It will be seen that theelements E, F, and K,1n combination form in substance a structureanalogous to a bowstring truss whosehorizontal member in itself is atruss, and which is preferably connected with the overhead member. Thisis also substantially the case however the upper and lower members areunited at the ends thereof.

I claim- In a truss the combination of the lower member, the uppermember, and the underneath truss, said lower member having a verticalseries of horizontal chords spaced apart from each other, said uppermember being arched, and said members and said underneath truss beingconnected at the ends and the central portion of the truss,substantiallyas described.

Witness'my hand this 6th day of June, 1892.

LUTHER PULLIAM. Witnesses:

C. D. MooDY, A. BoNvILLE.

